I had made a whole chat application using signalr as a socket with the online and offline facility. I am facing a few problems,
Signalr connection is always time out after some time, to overcome that I had condition if hubconnection is not connected then create new hubconnection (onResume app), but still it get hubconnection._callback got increased when sending message and not moving to server side socket. Again need to refresh whole app.
Can someone tell me whether this is problem because there are lot of operations going on and so signalr loses its connection as flutter is single thread and it cannot handle much? or should I use Isolate or inherit widget.
Summary problem:
I cannot send message in chat after sometime. It stores all message in hubconnection._callback and not going for server.
Is anything better solution to keep alive in both Android+iOS.
I had used https://pub.dev/packages/signalr_netcore package.
Please do not mention about firebase.
Any other logic suggestion is appreciable.
Thank you.
I've been using a different package, https://pub.dev/packages/signalr_core, which works fine without any particular issues what I have observed at the moment.
I'm only running about 10 listeners simultaneously, not sure if that is more or less than you. In the package I'm running you can establish connection with automatic reconnect. It looks like this:
HubConnectionBuilder().withAutomaticReconnect().withUrl(....)
It seems like your package have the same functionality... Have you tried that?
Related
Here's the code:
How to ensure the javascripts/channels/chatrooms.coffee is loading and receive: (data) works? Console.log data is not loading
I posted the problem the other day. It comes from a tutorial, but somewhere after continuing work on my project, I'm not sure where the bug came up,
But the message relay job posts on the server, and my config.yml has redis with redis up and running.
There have been similar bugs, but I've worked through those solutions and it's not enough. The received: (data) console log doesn't arrive in the js console of the browser.
The App subscriptions seem to all be in order according to the tutorial, I bet it's a really simple fix.
My messaging system still works, so it's not crucial to the project, but it's a difference of having the chat system work in realtime versus with a 4 second page-refresh delay.
The last problem I had was not including jquery for my other coffeescripts, so I'm guessing the channels coffeescripts is probably a one line fix.
I have an application (Laravel + MongoDB running on Nginx) where I pull some data from the database and render it on the screen. The application focusses on multiple real life objects. Once an object is turned on (is_on equals to true in the database), the timer on the screen needs to start ticking. Once the object is turned off (is_on equals to false in the database) the clock stops ticking and resets to 0. The format of the clock is HH:MM:SS. So it shows how long the real life object is turned on.
My problem is that I don't really now how to save/implement such timer. When the user request the page, I pull the necessary data from the database. If I also save the timer in the database, you have to make a query every second which is very bad practice.
I remembered something about WebSockets and tried to look into them. I actually managed to build a basic Hello World chat application, but don't really know how to implement this in my project. There is no place for it in the database (because of the queries), so I don't really know where to save that timer on the server. I'm also doubting if WebSockets are the way to go.
So are WebSockets the way to go and if it is, can you guys point me in the right direction on how to implement this? If not, can you advise me what I should do?
Thanks in advance!
From your question:
I understand that the objects you print in the screen are modified by
users in the application, and your aim is to live forward those
modifications to other active client instances of your application.
In that case, as you mention, I would point you to websockets. They are a great way to feed information directly to the client, so the client receives the update signals and modify the interface, with no need of user action.
In order to implement the logic to notify the client, I recommend using a push approach, but this is really depending on what kind of clients you'd like to notify, since the push world is still a bit tricky.
Further readings for this websocket based push implementation:
Question about Push Flags:
Difference between push and urgent flags in TCP
If your client runs in browser or mobile this question is nice to read:
How to send push notification to web browser?
Also html5 websockets:
http://www.websocket.org/aboutwebsocket.html
As a sidenote:
A nice architecture for client-server live communication is based on node.js together with socket.io library offering good performance and not really complex implementation if you know what you do.
I try to use txt-records to share information between multiple devices. Therefore I am using bonjour/avahi. The server-side works fine as wireshark proofs. Information is added to the txt-record and sent out using MDNS.
The problem occurs on the client side, where the daemon/service does not seem to get the information change all the time. It is stuck with information that is already outdated and does not automatically update it when I try to resolve the service again.
On the client side I am using DNSServiceResolve in combination with a callback function where I call TXTRecordContainsKey and TXTRecordGetValuePtr to make sure the data is available before use. This all works fine except that, as already mentioned, the information is not always updated.
Am I missing something, or are there any additional API-function calls that I can use to force the daemon to update its record except DNSServiceResolve?
Thank you in advance.
Solved, always make sure you deaktivate your firewall when dealing with such strange problems...
This completely solved my issue.
I am a little confused on how to go about and do this....
On each page of my app i connect to PHP file to drag in data from my server. I have about 10 pages. Now if there is no connection to the internet then of course now data can be received.
Often the app crashes and we are putting this down to not having the data due to a change in connection or wifi whatever.
Now i have setup the reachability thing and that works, but i dont know how to link this in with the PHP calls. Should i check the reachability and if no connection then dont run the call. If so, what about all the variables, they will still be null and cause an error then?
I dont really know what is the best solution.
Hope you can help
Alex
Are the php calls just to receive data from a database without using a built in DB framework such as SQLite? If so, I went the same route to avoid the headache at first, but running SQLite in your app is a better solution overall, and reduces multiple dependencies (such as internet connection).
Now if the php calls that give you data back are receiving this information from yet another source and then feeding it into its own DB.....
Should i check the reachability and if no connection then dont run the call
Yes you should. This is done in multiple apps already. What variables would be null in this case? Pop the code that makes the call in an "if" block below this check, and only run it if true. Error handling other variables that might be null because the php call isn't setting them is up to you. You can do this is multiple ways.
You should certainly cache the data so the App doesn't HAVE to connect to the internet to display something, other than that I would make sure to use asynchronous requests and the timeout feature of NSURLRequest to control your attempts to request data in the background. If you don't get the data, just keep using what you have cached.
I have an iPad app that works both on and offline but when I am offline there are web service calls that will need to be made once online availability is an option again.
Example:
A new client is added to the app, this needs to be sent to the web service but since we are offline we dont want to slow the user down so we let them add locally and keep going but we need to remember that that call needs to be made to the web service when we can. Same thing for placing orders and such.
Is there some sort of queue that can be setup that will fire once we have connectivity?
I don't think the overhead of a heavyweight tool like MSMQ is needed for a simple action. You can use Core Data, persist managed objects with the data needed to call the web service, and only delete each managed object after a successful post. There might or might not be a way to capture an event when connectivity starts, but you can certainly create a repeating NSTimer when the first message is queued and stop it when there are no messages in the queue.
This library handles offline persistent message queueing for situations like you describe. It says alpha from a year ago, but I have confirmed it is used in production apps:
https://github.com/gcamp/IPOfflineQueue